I did a quick forum search and I'm not sure I have the same issues others have had with needing to install expansion tanks.
When I turn on either hot or cold (or mixed) the initial pressure is somewhere around 150psi (confirmed with a gauge at the hose outside). Then after 10-20 seconds or so the pressure tapers off and drops to around 40psi or so which isn't sufficient for this two story house. We had higher pressure before I adjusted the PRV but had the same symptoms described above (just with a higher running pressure). I thought the problem might have been with the PRV setting so I cranked it down.
Could it still be thermal expansion even though it happens with the cold side as well? What other troubleshooting can I do?
When I turn on either hot or cold (or mixed) the initial pressure is somewhere around 150psi (confirmed with a gauge at the hose outside). Then after 10-20 seconds or so the pressure tapers off and drops to around 40psi or so which isn't sufficient for this two story house. We had higher pressure before I adjusted the PRV but had the same symptoms described above (just with a higher running pressure). I thought the problem might have been with the PRV setting so I cranked it down.
Could it still be thermal expansion even though it happens with the cold side as well? What other troubleshooting can I do?